Conclusions
The DLP and CCLP models at various risk levels are developed for different type of agricultures (rainfed and irrigated) and seasons (monsoon and winter) to maximize the net annual benefit from a coastal groundwater basin in Eastern India under various resource constraints. The decision variables of the model are seasonal cropping pattern and water resources (surface water and groundwater) allocation. The DLP model shows an increase in net annual return with the increasing in deviations from the existing cropping pattern, utilizing the available water resources. The CCLP model shows an increase in net annual return with the percent increase of risk levels whereas the optimal cropping pattern remains constant both in DLP and CCLP at 10% risk level. The 40% deviation from the existing cropping pattern was found as the optimal that satisfies the minimum food requirement and maintains geo-hydrological balance of the basin. The sensitivity analysis for conjunctive use of surface and ground water resources shows that 20% surface water and 30% groundwater as the optimum water allocation policy for the study area. So, the landholders are suggested to replace existing cropping pattern by the proposed optimal cropping so as to stabilize their socio-economic development with the sustainable management of available land and water resources.
For sustainable hydrological balance of the coastal groundwater basin, the developed scenarios of optimal cropping pattern and water resources allocation under deterministic and stochastic environment will be useful for landholders and district administrators. The developed DLP and CCLP models are found as effective tools for socio-economic development of the basin and can be applied to any region with the variation in resource constraints.